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CSC - Cost-sharing contracts

Objective

The project is focused on the realisation of quantum communication with continuous variables such as the quadrature amplitudes of the quantized electromagnetic field. The advantage of using these highly excited quantum systems involving many photons in a light field, over single particle quantum systems is the prospect for high optical data rates and simple processing tools, based upon techniques used in telecommunication. The main objectives of the project are transfer and storage of continuous quantum information encoded on light and on matter systems, and the implementation of quantum cryptography using quantum continuous variables. This project addresses objective 3 "Long distance and secure communication" of the QIPC workprogram. The specific items of the workplan will be the development and assessment of many-photon entangled state sources, of quantum repeaters and memories, and the implementation of quantum teleportation and quantum cryptography. The project is focused on the realisation of quantum communication with continuous variables such as the quadrature amplitudes of the quantized electromagnetic field. The advantage of using these highly excited quantum systems involving many photons in a light field, over single particle quantum systems is the prospect for high optical data rates and simple processing tools, based upon techniques used in telecommunication. The main objectives of the project are transfer and storage of continuous quantum information encoded on light and on matter systems, and the implementation of quantum cryptography using quantum continuous variables. This project addresses objective 3 "Long distance and secure communication" of the QIPC workprogram. The specific items of the workplan will be the development and assessment of many-photon entangled state sources, of quantum repeaters and memories, and the implementation of quantum teleportation and quantum cryptography.

DESCRIPTION OF WORKContinuous quantum Variables (QCV) provide a new approach to quantum information processing and quantum communication. It uses highly exited quantum systems, such as quadrature amplitudes of the light field. While keeping the known benefits of discrete quantum systems, continuous variables offer additional advantages over the single photon systems predominantly studied so far. Among these advantages are the prospect for high optical data rates and simple processing tools. Within the present project the following items will be explored:1. The demonstration and the implementation of light sources with entangled QCV; including amplification of single photon sources;2. The design of practical ways for transfering information between QCV encoded on matter and on light observables, i.e. read-in read-out of quantum memories;3. The demonstration of the transmission of quantum information with bright light sources;4. The elaboration of new schemes for quantum cryptography with QCV, including the exploration of the relevant schemes for entanglement purification and quantum error correction.

The background of this proposal is provided by the results of the past years on squeezing, quantum non-demolition measurements, noiseless manipulation of optical beams obtained in the framework of previous ESPRIT projects. It was shown recently that these methods allow one to manipulate quantum entanglement and EPR correlations, which are crucial features to reach the QIPC domain.